feat: update service worker to handle push and notificationclick

Additional event handling for use by the upcoming web-push plugin.

public/src/service-worker.js

@@ -17,3 +17,52 @@ self.addEventListener('fetch', function (event) {
 		return response;
 	}));
 });
+
+/**
+ * The following code is used by nodebb-plugin-web-push
+ * There is a very strong argument to be made that this is plugin-specific
+ * code and does not belong in core.
+ *
+ * Additional R&D is required to determine how to allow plugins to inject
+ * code into the service worker.
+ */
+
+// Register event listener for the 'push' event.
+self.addEventListener('push', function (event) {
+	// Keep the service worker alive until the notification is created.
+	const { title, body, data } = event.data.json();
+	event.waitUntil(
+		self.registration.showNotification(title, { body, data })
+	);
+});
+
+self.addEventListener('notificationclick', (event) => {
+	event.notification.close();
+	let target;
+	if (event.notification.data && event.notification.data.url) {
+		target = new URL(event.notification.data.url);
+	}
+
+	// This looks to see if the current is already open and focuses if it is
+	event.waitUntil(
+		self.clients
+			.matchAll({
+				type: 'window',
+				includeUncontrolled: true,
+			})
+			.then((clientList) => {
+				// eslint-disable-next-line no-restricted-syntax
+				for (const client of clientList) {
+					const { hostname } = new URL(client.url);
+					if (target && hostname === target.hostname && 'focus' in client) {
+						client.postMessage({
+							action: 'ajaxify',
+							url: target.pathname,
+						});
+						return client.focus();
+					}
+				}
+				if (self.clients.openWindow) return self.clients.openWindow(target.pathname);
+			})
+	);
+});